摘要 |
Air from an air source A, which may be the bleed air of an aircraft, enters the system under the control of an air flow control unit (10). An organic fuel from a fuel reservoir (12 or 13) enters a mixing chamber (16) under the control of fuel flow control unit (14) for mixture with the air. At a first stage the organic fuel is a oxygenated organic fuel from reservoir (12), and at a subsequent stage the organic fuel is a hydrocarbon fuel from reservoir (13). The air and fuel mixture passes to a catalyst bed (18) containing a noble metal catalyst such as platinum, palladium or a mixture thereof. A relatively low temperature, non-flaming reaction occurs and the resultant gas mixture contains a low concentration of oxygen and larger qualities of inert gases such as nitrogen, carbon dioxide and water vapour. This post reaction mixture, which leaves the system at B, is suitable for suppressing and extinguishing fires, and is especially suitable for purging of air from cargo compartments on board aircraft during a flight on detection of a fire. A temperature control unit (20) associated with the catalyst bed (18) may be used to prevent its overheating during the reaction. A control unit (24) operates to control the air flow control unit (10), the fuel flow control unit (14) and the temperature control unit (20) in response to signals from sensing units (22) at various points in the system which detect various parameters such as the gas, pressure, temperature and flow.
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